Horizontally swinging bracket supported seat



EDG/1l? W. Mdc/(NIGHT BY MYX5/Mey H/s ATTORNEYS NOV 8, 1955 E. w. MaGKNlGHT HORIZONTALLY SWINGING BRACKET SUPPORTED SEAT original Filed April 13, 1949 United States Patent O HORIZON TALLY SWNGING BRACKET SUPPORTED SEAT Edgar W. MacKnight, San Leandro, Calif.

Continuation of application No. 218,733, filed April 2, 1951, which is a division of application No. 87,277, filed April 13, 1949, now Patent No. 2,572,874, granted (lctober 30, 1951. Also division of application No. 183,245, filed September 5, 1950, Patent No. 2,650,647, granted September 1, 1953. This application August 10, 1953, Serial No. 373,349

12 Claims. (Cl. 155--81) My invention relates to adjustable seats and more particularly to a seat assembly for technicians such as dentists, to permit such technicians to operate while comfortably seated.

This application combines the claimed subject matter of my application for Adjustable Auxiliary Seat Assembly, Serial No. 218,733, filed April 2, 1951, as a division of application, Serial No. 87,277, filed April 13, 1949 (now Patent No. 2,572,874 of October 30, 1951), and the claimed subject matter required to be divided out of my application for Adjustable Seat Assembly, Serial No. 183,245, tiled September 5, 1950, now Patent No. 2,650,647, granted September 1, 1953.

Among the objects of my invention are:

(l) To provide a novel and improved adjustable seat assembly, particularly for use by dentists or the like when working on patients;

(2) To provide a novel and improved adjustable seat assembly for dentists or the like, which will facilitate the approach and retreat of an operator with respect to a patient in a patients chair;

(3) To provide a novel and improved seat assembly for dentists, which will permit such dentist or the like to move with greater ease and comfort to any desired position with respect to a patient;

(4) To provide a novel and improved seat` assembly for dentists or the like, which will permit movement by the operator to any desired position with respect to a patient, and afford such operator a stronger feeling of security while operating on` such patient.

Additional objects of my invention will be brought out in the following description of a preferred embodiment of the same taken in conjunction with the accompanying drawings wherein- Figure l is a View in section of a seat assembly embodying the features of the present invention and illustrating the manner of tying the same in with a patients chair;

Figulre 2 is a View in section, taken in the plane 2-2 of Figure 1;

Figure 3 is a view in section, taken in the plane 3 3 of Figure 2; and

Figure 4 is a view depicting a structural detail of the assembly of Figure 1.

The invention, as illustrated in the drawings, includes a wheel truck 1 involving a trough member 3 having depending side walls 5 and 7, and between these side 7 by providmg firm` anchorage for the vertical channel member.

rice

' This vertical channel supports a bracket 19 on which a tongue 21 may be slidably adjusted as to elevation, such bracket constituting a pair of spaced bracket blocks 22 and 23 inserted .within the channel member and welded or otherwise aixed thereto, and to the exposed ends of these two blocks, there is bolted a bracket plate 25 of a width such that its vertical edges extend slightly beyond the bracket blocks to either side thereof.

The aforementioned tongue 21 involves a length of channel member, preferably slightly tapered for appearance sake, with its broad end toward the bracket plate to which it is adjustably fixed for elevational adjustments. This is accomplished by aftixing to each side of the tongue at its broad end, a clamping plate 27 which overhangs or extends beyond the end of the tongue suciently to permit of the formation of a groove 29 adapted to receive an edge of the bracket plate. A clamping bolt 31 passing through the tongue and clamping plates constitutes means for drawing the clamping plates toward each other for clamping the tongue to the bracket plate at any desired' position along such brack et plate. v

Such vertical adjustment of the tongue permits the seat assembly to be accommodated to chairs of different designs and styles, as placed on the market by different manufacturers, thus enabling the tongue to clear operating pedals, engine rheostat, etc., as well as the base flange of the patients chair, which allows the operator to move in close to the patient.

At its narrow end, the tongue terminates in a pivot yoke 33 having its legs lying in parallel horizontal planes,

and perforated to receive a vertically disposed clamping bolt 35.

The inner member of the telescopic standard constitutes a tube 37 which carries the seat 39 and associated mechanism 40. It is telescopically supported within the vertical channel member by providing aligned openings in the bracket blocks 22, 23 of a size sufficiently to slidably receive the tube, and at the upper end of the vertical channel member, there is provided means 43 for locking such tube in any vertically adjusted position.

Such means comprises a rectangular housing of two sections, namely, a lower section 45 which is integrally united to the upper end of the vertical channel member, and an upper section 47 which provides a matching t with the lower section. The upper section is held to the lower section by a bolt 49, both sectionshaving vertically aligned openings to permit passage of the tube 37.

Within the housing is a locking plate 51 which has a central beveled opening therethrough, through which the tube may comfortably pass when such locking plate is in a horizontal position. At one end, this locking plate is loosely supported between a shoulder 53 and a ange 55 formed by suitably crimping a piece of sheet metal and welding the same into the lower section of the housing, while at its opposite end, the plate is provided with a perforation through which the bolt 49 passes, the plate being normally urged downwardly at this end, against the tube 37 by a compression spring 57 thereabove. Disposed below the locking plate in line with the compression spring 57, is a lip S9 constituting one end of a lever 61, preferably in the form of a stiff wire loop which extends through a wall of the housing and fulcrums on the edge of the opening through which it passes. Under the action ofthe compression spring, the tube will, in the absence of any opposing force, remain in its prevailing adjustment, and any weight or pressure applied to the upper end of the tube, as when one sits upon the seat, will only serve 0 to enhance the binding effect of the locking plate thereon.

When it is desired to adjust or change the elevational position of the seat which is carried on the tube, a downward pressure on the exposed end of the lever, will lift the lower end of the locking plate, thereby bringing the plate to a horizontal plane, whereby the tube will be freed for movement along its vertical axis.

A's previously indicated, the tube 37 carries the seat 39 and its associated mechanism 4t). Such associated mechanism includes a rod or shaft 63 journaled in bearings 65, 67 disposed, one at each end of the tube. This shaft extends beyond the upper end of the tube and at this end, there is xedly mounted an arm 69 which terminates at its other end in a bearing 71, in which is journaled a short shaft 73 which protrudes from the bearing at either end thereof. At its upper end, this short shaft has aflxed thereto a seat arm '75 in the free end of which is journaled the stem 77 of a suitable seat 39, spaced bearings being preferably provided for this purpose.

As thus far described, the path of movement of the seat with respect to the axis of the supporting tube, is indeterminable and not fixed. This is so because, under the circumstances, the seat is 'adapted to swing indiscriminately about the short shaft as an axis, while at the same time, the short shaft is adapted to swing indiscriminately about the axis of the supporting tube. Therefore, in order to pre-establish the permissible path of movement of the seat with respect to the axis of the supporting tube, both of the aforementioned swinging movements must be controlled withrespect to each other.

This I accomplish by xedly mounting on the upper end of the tube, a sun gear 79, while at the lower end of the short shaft 73, I provide a planetary gear 81, and then connect the two gears by some drive means such as a chain drive 83. With such a connection, any swinging movement on the part ofl the short shaft in an arc about the axis of the supporting tube, will cause the seat to swing in an arc in opposite direction about the short shaft axis.

By selecting a proper relationship between the ratio of arm lengths and the gear ratio, substantially linear movement of the seat may be realized and along a path through the axis of the supporting tube. A gear ratio of two to one between the sun gear and planetary gear will satisfy the requirements, where both arms are of the same length.

To assure that such linear movement shall be conned to a particular direction, namely, along the axis of the tongue, which will then provide for linear movement toward and away from a patient, the seat and its associated mechanism should be initially assembled so that a line joining the axis of the supporting tube and the center of the seat, shall sight along the axis of the tongue, and to assure maintenance of such directional adjustment, the sun gear must be fixed against rotation on its axis. This is accomplished by afl'ixing a guide rib 85 along the back of the bracket plate and slidably engaging the same by a guide block 87 aixed to the tube 37.

Extending upwardly from the sun gear, are a pair of stop pins 89, 91 disposed on a line preferably slightly off center. Such stop pins stand in the path of movement of the planetary arm 69 both as to its extreme forward and return swing positions, and thus preclude the short Shaft from ever reaching a dead center position on a straight line joining the anchored end of the arm 69 and the seat end of the arm 75, which might interfere with smooth, effortless movement of the seat. Ease of movement of the seat between its forward and retracted positions will, therefore, always be assured.

A shroud 93 may be installed over the planetary gear arrangement and, when so installed, is held out of contact with the chain drive by a bolt 95 extending through the planetary arm.

The entire seat assembly is designed for arcuate travel about the bolt axis located at the end of the tongue, and accordingly, to facilitate such movement, the truck wheel yokes 9 are installed on a slight angle to the longitudinal axis cf the trough member 3 so as to cause the wheels to describe an are about such pivot point without drag.

iX/leans for fastening the seat assembly to a dental chair Preferably takes the form of .a p ivet past A1,03, provision being made for anchoring the saine to the lower rim of the base of the patients chair by means of a suitable clamp. Such clamp may involve an arcuate trough section 109 adapted to lit over the rim of the chair base, leaving an exposed upper horizontal flange 111 to which may be attached one end of the pivot post.

Such attachment is preferably by way of a ball and socket connection, the rim being raised at the point of connection to provide a socket 113, while the pivot post, at its point of connection, has a tubular lower end 114 which is threaded internally for the reception of a bolt 115 passing through the ange of the clamp, with its head fitting into the socket. By constricting the neck of the bolt, a certain latitude of movement for the pivot post will be permitted at this point.

By providing a lateral perforation through the lower end of the pivot post to expose certain of the threads on the bolt, and then deforming such threads with a suitable tool, the pivot post connection to the clamp may be made permanent- The pivot post is preferably made extensible by making it of telescoping parts, namely a pivoted tubular element 114 with a sleeve 119 slidable thereon, and then providing means for supporting the sleeve at different elevational positions on the tubular element. This can be readily accomplished by laterally perforating the pivoted element at spaced points longitudinally, and providing a pair of diametrically disposed openings in the sleeve, which are adapted to line up with selected perforations in the pivoted element. The perforations in the sleeve are preferably of larger diameter than lthe openings in the pivoted element to receive the head and nut of a clamping bolt 123 passing through the aligned holes, whereby, upon tightening the nut on such bolt, the tightening pressure will be applied solely to the pivoted element, and sufficiently to compress the same and cause corresponding expansion in a normal direction against the sleeve, to thereby bind the same against movement with respect to the pivoted element.

At its upper end, the sleeve is closed except for a threaded axial opening for the reception of the pin or bolt ,35. Such bolt is adapted to pass through the perforations in the yoke at the end of the tongue prior to threading the bolt into the upper end of the sleeve for securing the seat assembly to the pivot post. A suitable spacing collar 1,25 may be applied to the bolt for disposition between the spaced arms of the pivot yoke, to rigidify the connection at this point, so that all pivot movement will occur at the lower end of the pivot post.

The ball and socket pivot connection of the pivot post to the clamp not only provides for the arcuate travel of the entire seat assembly as indicated, but permits the seat assembly to ride over obstructions or irregularities without transmitting undue strain to any part of the device.

Ordinarily, in the average installation, the weight of the patients chair on the lower ange of the clamp will be sufficient to hold the pivot post installation in place, but in the event such chair should be susceptible to creeping, the upper ange of the clamp may be provided with one or more threaded openings 126 for the reception Aofclamping screws which may be tightened down against the rim of the base of the chair.

In accordance' with the preferred form of the present invention, I provide means for normally restraining movement of the seat from its retracted position, in the absence of an overpowering force, and such means preferably takes the form of a at coil spring 129 encircling the sun gear and having one end anchored in said gear and its other end hooked around the lower end of the bolt 95, which is the same as being anchored to the planetary arm 69. The spring is preferably disposed in a circumferential groove 131 formed in the gear, by anchoring one end of a length of spring wire in a recess 133 in a wall of such groove, wrapping such wire around the gear and then hooking its free end about the bolt 95.

Any force sufficient to overcome the resistance offered by the spring, will cause the seat to move forward, the spring in the meantime being wound tighter to build up a sufficient restoring force, so that upon removal of said overcoming force, the seat will be restored to its retracted position. Under these conditions, the entire seat assembly may now be adjusted to a slight tilt angle with the vertical, say of the order of 2 to 5 degrees, without the seat shifting from its retracted position. This may be accomplished by raising the broad end of the tongue 21 or shortening the pivot post 103, or by a combination of the two adjustments. One of the advantages derived from this relationship resides in the fact that the weight of the operator on the seat will provide a component of force in the forward direction of its movement, thus facilitating the use of the seat assembly in carrying the operator toward the patient. 4 j

Working from a seat so tilted, places the operator 1n a more comfortable and relaxed posture, at the same time avoiding the necessity of consciously holding the seat against retraction by the spring, thus enabling the operator to work more effectively and eiciently. t n

From the above description of my invention in 1ts` preferred form, it Will become apparent that the same fullls all the objects of my invention as previously stated, and while l have described my invention in considerable detail, the same is subject to alteration and modification without departing from the underlying principles thereof, and I, therefore, do not desire to be limited in my protection to such details, except as may be necessitated by the appended claims.

I claim:

l. A seat assembly comprising a pair of arms, means connecting said arms for angular movement, one with respect to the other, means pivotally mounting said connected arms at the free end of one of them to a mounting support, means at the free end of the other of said arms for carrying a seat, a seat carried by said last means, and means responsive to lateral pressure against such a seat, for causing said arms to swing in opposite directions simultaneously with respect to each other.

2. A seat assembly comprising a pair of arms of equal length, means connecting said arms on a common axis for angular movement, one with respect to the other, means pivotally mounting said connected arms at the free end of one of them to a mounting support, means at the free end of the other of said arms for carrying a seat, a seat carried by said last means, and means responsive to lateral pressure against such a seat, for causing said arms to swing in opposite directions simultaneously.

3. A seat assembly comprising a pair of arms of equal length, means connecting said arms on a common axis for angular movement, one with respect to the other, means pivotally mounting said connected arms at the free end of one of them to a mounting support, means at the free end of the other of said arms for carrying a seat, a seat carried by said last means, and means responsive to lateral pressure against such a seat, for causing said arms to swing in opposite directions simultaneously, said last means involving a sun gear xedly mounted on said pivotal supporting means, a planetary gear supported on said common axis, said sun gear and planetary gear being in drive connection.

4. A seat assembly comprising a sun gear; means supporting said sun gear at a desired elevation in a substantially horizontal plane; a planetary gear; means supporting said planetary gear in a substantially horizontal plane for movement in an orbit about said sun gear, said means including a planetary arm extending from said sun gear supporting means and swingable about the axis of said sun gear, with said planetary gear journaled adjacent the free end of said arm; a seat supporting arm; a seat carried by said seat supporting arm; means connecting said seat supporting arm with said planetary gear; a drive connection between said gear and said planetary gear; and

stop means for restricting the swing of said planetary arm to less than degrees to preclude dead center positionng of said arms.

5. A seat assembly comprising a sun gear; means adjustably supporting said sun gear at a desired elevation in a substantially horizontal plane; a planetary gear; means supporting said planetary gear in a substantially horizontal plane for movement in a circular orbit about said sun gear, said means including a planetary arm extending from said sun gear elevation-adjusting means and swingable about the axis of said sun gear, with said planetary gear journaled adjacent the free end of said arm; a seat supporting arm; a seat carried by said seat supporting arm; means connecting said seat supporting arm into a rigid assembly with said planetary gear; a chain drive connection between said sun gear and said planetary gear; and stop means for restricting the swing of said planetary arm to less than 180 degrees to preclude a dead center positioning of said arms, said means including a pair of stop pins substantially diametrically disposed with respect to said sun gear and in the path of movement of said planetary arm.

6. A seat assembly comprising a sun gear; means adjustably supporting said sun gear at a desired elevation in a substantially horizontal plane; a planetary gear; said sun gear and said planetary gear having a tooth ratio of two to one; means supporting said planetary gear in a substantially horizontal plane for movement in a circular orbit about said sun gear, said means including a planetary arm extending from said sun gear elevationadjusting means and swingable about the axis of said sun gear, with said planetary gear journaled adjacent the free end of said arm; a seat supporting arm of a length similar to that of said planetary arm; a seat carried by said seat supporting arm; means connecting said seat supporting arm into a rigid assembly with said planetary gear; a chain drive connection between said sun gear and said planetary gear; and stop means for restricting the swing of said planetary arm to less than 180 degrees to preclude a dead center positioning of said arms, said means including a pair of stop pins substantially diametrically disposed with respect to said sun gear and in the path of movement of said planetary arm.

7. A seat support comprising a pair of arms, means connecting said arms for angular movement, one with respect to the other, a support, means pivotally mounting said connected arms at the free end of one of them to said support, means at the free end of the other of said arms for carrying a seat, means responsive to pressure against such seat for causing said arms to swing in opposite directions with respect to each other, and means resisting such movement.

8. A seat supp'ort comprising a pair of arms, means connecting said arms for angular movement, one with respect to the other, a support, means pivotally mount ing said connected arms at the free endof one of them to said support, means at the free end of the other of said arms for carrying a seat, means responsive to pressure against such seat for causing said arms to swing in opposite directions simultaneously with respect to each other, and spring means resisting such movement to build up a restoring force for release upon removal of such pressure.

9. A seat support comprising a pair of arms, means connecting said arms for angular movement, one with respect to the other, a support, means pivotally mounting said connected arms at the free end of one of them to said support, means at the free end of the other ot said arms for carrying a seat, means responsive to pressure against such seat for causing said arms to swing in opposite directions simultaneously with respect to each other, and spring means resisting such movement to build up a restoring force for release upon removal of such pressure, said means involving a coil spring, one end of which is anchored to said pressure responsive means and the other end to one of said arms.

10. A seat support comprising a sun gear; means supporting said sun gear at a desired elevation; a planetary gear; means supporting said planetary gear for Inovement in an orbit about said sun gear, said means including a planetary arm extending from said sun gear supporting means and swingable about the axis of said sun gear, with said planetary gear journaled adjacent the free end of said arm; a seat supporting arm; means connecting said seat supporting arm at one end with said planetary gear; a drive connection between said sun' gear and said planetary gear; and means normally resisting movement of said planetary gear about `said sun gear.

11. A seat support comprising a sun gear; means supporting said sun gear at a desired elevation; a planetary gear; means supporting said planetary gear for movement in an orbit about said sun gear, said means ineluding a planetary arm extending from said sun gear supporting means and swingable about the axis of said sun gear, with said planetary gear journaled adjacent the free end of said arm; a seat supporting arm; means connecting said seat supporting arm at one end with said planetary gear; a drive connection between said sun gear and said planetary gear; and spring means normally resisting movement of said planetary gear about said s un gear to build up a restoring force in the presence of an overpowering force.

12. A seat support comprising a sun gear; means supporting said sun gear at a desired elevation; a 'planetary gear; means supporting said planetary gear 4for movement in an orbit about said sun gear, Said means including a planetary arm extending from said sun gear supporting means and swingable about the axis of said sun gear, with said planetary gear journaled adjacent the free end of said arm; a seat supporting arm; means com necting said lseat supporting arm at one end with said planetary gear; a drive connection between said sun gear and said planetary gear; and spring means normally resisting movement of said planetary gear about said sun gear to build up a restoring force in the presence of an overpowering force, said means involving a coil spring having one Vend 'anchored in said sun gear and its other end to said planetary arm.

References Cited in the le of this patent UNITED STATES PATENTS 604,417 Richardson May 24, 1898 1,147,896 Schroeder luly 27, 1915 1,337,221 Hansen Apr. 20, i920 1,379,263 Jellinek May 24J 1921 *444A WIM j 

